Athletic movements like throwing and kicking, though ostensibly involving only a major extremity, actually involve a complex interaction of a multitude of muscular and skeletal components across the entirety of the body. These muscular and skeletal components work simultaneously and serially to produce a given body movement. For example, during the action of throwing a baseball, the body will go through a large number of movements that typically begins with the thrower moving the throwing arm backwards relative to the target while simultaneously pulling the opposite leg up and back. From this position, the raised opposite leg is thrust toward the target so as to pull the body toward the target. At the same time, the grounded leg drives the body in the same direction. As the body is pulled and driven toward the target, it pulls the throwing arm along with it. The throwing arm is moved at high velocity so that the hand on the arm is, in turn, pulled and snapped like a whip by the throwing arm. The velocity imparted to the hand is transferred to the ball and the ball released while the hand is in motion. The interaction of the muscular and skeletal components during such a process is called the kinetic chain.
Over the past few decades, exercise devices have appeared that are designed to train and strengthen the components of the body used during the sport-specific, complicated movements like throwing or kicking. These devices use oppositional resistance against the body itself or the separate body parts to train the body at speeds akin to those involved in the particular sport-specific movement. For example, several such devices appear in United States Published Patent Application No. 5080300118 (“Wehrell”). These prior art devices, apply one or more lateral resistive loads to participants performing complex motions at low or high speeds. The intent is to condition the body to eventually perform these complex movements at competition speed by applying low-level resistance.
With the prior art device, resistive bands or cables are spooled in mechanical assemblies. The bands or cables emanate from the mechanical assemblies and are fed through pulley assemblies that can be located at various vertical or horizontal positions. The ends of the bands or cables include attachment means to allow attachment of the bands or cables to body parts or a harness. For example, as shown in Wehrell FIG. 36, for a person engaged in training a throwing motion, the device will provide for resistive loads to be applied to the wrist, waist and ankles.
Though the prior art devices are highly useful in training the components of the kinetic chain, one deficit of the prior art devices is their complexity. Of note, the devices tend to be complicated devices having the bands or cables (“resistance lines”) emanating from mechanical assemblies and fed through independently positionable pulley assemblies. The resistance lines project from these pulley assemblies on the main structure of the device and attach either directly to a body part on the user or to a garment worn by the user. To properly employ the device, the person setting up the device (which could be the athlete user, but is more typically a trainer training the athlete) must select resistance lines of the proper length and resistance to attach to the several body parts or the garment.
In addition to selecting the proper lengths and resistances for the resistance lines, the person adjusting the device will need to select the proper origin point for the resistance lines. For example, in the Wehrell device the positioned pulley assemblies can be slidably moved along rails or positioned on a peg board surface and locked into place. Once locked, the positioned pulley assemblies represent an effective origin point for the cable or band leading to the body part of the user.
One deficit with the prior art device is that it offers the user a daunting number of options of where to position the origin points. However, it has been shown that to properly train the body parts involved in a kinetic chain movement, the resistive force applied to a body part should emanate from a localized area so that involved muscles receive optimal loading and involved ligaments and tendons are not dangerously torqued or stressed by application of misdirected loading. For example, in the case of a pitching movement, if the load applied to the forearm on the throwing arm emanates from too high or low of an origin point, the elbow and wrist joints can be improperly leveraged, which can result in counter-productive injury to the user. Similarly, another deficit of the prior art device is that it does not cue the user on how to perform a particular exercise. Of particular usefulness to the user is an indication of the body position to assume when initiating resistance training for a sport-specific movement.